[PATCH] macfb: fix a memory leak (CID 1465231)

[PATCH] macfb: fix a memory leak (CID 1465231)

[Laurent Vivier]

Rewrite the function using g_string_append_printf() rather than
g_strdup_printf()/g_strconcat().

Fixes: df8abbbadf74 ("macfb: add common monitor modes supported by the MacOS toolbox ROM")
Cc: mark.cave-ayland@ilande.co.uk
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
---
 hw/display/macfb.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/hw/display/macfb.c b/hw/display/macfb.c
index 4b352eb89c3f..277d3e663331 100644
--- a/hw/display/macfb.c
+++ b/hw/display/macfb.c
@@ -440,21 +440,18 @@ static MacFbMode *macfb_find_mode(MacfbDisplayType display_type,
 
 static gchar *macfb_mode_list(void)
 {
-    gchar *list = NULL;
-    gchar *mode;
+    GString *list = g_string_new("");
     MacFbMode *macfb_mode;
     int i;
 
     for (i = 0; i < ARRAY_SIZE(macfb_mode_table); i++) {
         macfb_mode = &macfb_mode_table[i];
 
-        mode = g_strdup_printf("    %dx%dx%d\n", macfb_mode->width,
+        g_string_append_printf(list, "    %dx%dx%d\n", macfb_mode->width,
                                macfb_mode->height, macfb_mode->depth);
-        list = g_strconcat(mode, list, NULL);
-        g_free(mode);
     }
 
-    return list;
+    return g_string_free(list, FALSE);
 }
 
 
@@ -643,7 +640,7 @@ static bool macfb_common_realize(DeviceState *dev, MacfbState *s, Error **errp)
         gchar *list;
         error_setg(errp, "unknown display mode: width %d, height %d, depth %d",
                    s->width, s->height, s->depth);
-        list =  macfb_mode_list();
+        list = macfb_mode_list();
         error_append_hint(errp, "Available modes:\n%s", list);
         g_free(list);
 
-- 
2.31.1

Re: [PATCH] macfb: fix a memory leak (CID 1465231)

[Peter Maydell]

On Fri, 5 Nov 2021 at 16:52, Laurent Vivier <laurent@vivier.eu> wrote:
>
> Rewrite the function using g_string_append_printf() rather than
> g_strdup_printf()/g_strconcat().
>
> Fixes: df8abbbadf74 ("macfb: add common monitor modes supported by the MacOS toolbox ROM")
> Cc: mark.cave-ayland@ilande.co.uk
> Reported-by: Peter Maydell <peter.maydell@linaro.org>
> Suggested-by: Peter Maydell <peter.maydell@linaro.org>
> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
> ---
>  hw/display/macfb.c | 11 ++++-------
>  1 file changed, 4 insertions(+), 7 deletions(-)
>
> diff --git a/hw/display/macfb.c b/hw/display/macfb.c
> index 4b352eb89c3f..277d3e663331 100644
> --- a/hw/display/macfb.c
> +++ b/hw/display/macfb.c
> @@ -440,21 +440,18 @@ static MacFbMode *macfb_find_mode(MacfbDisplayType display_type,
>
>  static gchar *macfb_mode_list(void)
>  {
> -    gchar *list = NULL;
> -    gchar *mode;
> +    GString *list = g_string_new("");
>      MacFbMode *macfb_mode;
>      int i;
>
>      for (i = 0; i < ARRAY_SIZE(macfb_mode_table); i++) {
>          macfb_mode = &macfb_mode_table[i];
>
> -        mode = g_strdup_printf("    %dx%dx%d\n", macfb_mode->width,
> +        g_string_append_printf(list, "    %dx%dx%d\n", macfb_mode->width,
>                                 macfb_mode->height, macfb_mode->depth);
> -        list = g_strconcat(mode, list, NULL);
> -        g_free(mode);
>      }
>
> -    return list;
> +    return g_string_free(list, FALSE);

This reverses the order compared to the old code (which prepends
'mode' to the 'list' string it is building up). Does that matter ?

-- PMM

Re: [PATCH] macfb: fix a memory leak (CID 1465231)

[Laurent Vivier]

Le 05/11/2021 à 18:01, Peter Maydell a écrit :
> On Fri, 5 Nov 2021 at 16:52, Laurent Vivier <laurent@vivier.eu> wrote:
>>
>> Rewrite the function using g_string_append_printf() rather than
>> g_strdup_printf()/g_strconcat().
>>
>> Fixes: df8abbbadf74 ("macfb: add common monitor modes supported by the MacOS toolbox ROM")
>> Cc: mark.cave-ayland@ilande.co.uk
>> Reported-by: Peter Maydell <peter.maydell@linaro.org>
>> Suggested-by: Peter Maydell <peter.maydell@linaro.org>
>> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
>> ---
>>   hw/display/macfb.c | 11 ++++-------
>>   1 file changed, 4 insertions(+), 7 deletions(-)
>>
>> diff --git a/hw/display/macfb.c b/hw/display/macfb.c
>> index 4b352eb89c3f..277d3e663331 100644
>> --- a/hw/display/macfb.c
>> +++ b/hw/display/macfb.c
>> @@ -440,21 +440,18 @@ static MacFbMode *macfb_find_mode(MacfbDisplayType display_type,
>>
>>   static gchar *macfb_mode_list(void)
>>   {
>> -    gchar *list = NULL;
>> -    gchar *mode;
>> +    GString *list = g_string_new("");
>>       MacFbMode *macfb_mode;
>>       int i;
>>
>>       for (i = 0; i < ARRAY_SIZE(macfb_mode_table); i++) {
>>           macfb_mode = &macfb_mode_table[i];
>>
>> -        mode = g_strdup_printf("    %dx%dx%d\n", macfb_mode->width,
>> +        g_string_append_printf(list, "    %dx%dx%d\n", macfb_mode->width,
>>                                  macfb_mode->height, macfb_mode->depth);
>> -        list = g_strconcat(mode, list, NULL);
>> -        g_free(mode);
>>       }
>>
>> -    return list;
>> +    return g_string_free(list, FALSE);
> 
> This reverses the order compared to the old code (which prepends
> 'mode' to the 'list' string it is building up). Does that matter ?
> 

Not at all. Perhaps it's even better like that as we have lower resolutions first.

It was done like that to be able to pass list set to NULL (first parameter must not be NULL).

Thanks,
Laurent

Re: [PATCH] macfb: fix a memory leak (CID 1465231)

[Peter Maydell]

On Fri, 5 Nov 2021 at 18:32, Laurent Vivier <laurent@vivier.eu> wrote:
>
> Le 05/11/2021 à 18:01, Peter Maydell a écrit :
> > On Fri, 5 Nov 2021 at 16:52, Laurent Vivier <laurent@vivier.eu> wrote:
> >>
> >> Rewrite the function using g_string_append_printf() rather than
> >> g_strdup_printf()/g_strconcat().
> >>
> >> Fixes: df8abbbadf74 ("macfb: add common monitor modes supported by the MacOS toolbox ROM")
> >> Cc: mark.cave-ayland@ilande.co.uk
> >> Reported-by: Peter Maydell <peter.maydell@linaro.org>
> >> Suggested-by: Peter Maydell <peter.maydell@linaro.org>
> >> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
> >> ---
> >>   hw/display/macfb.c | 11 ++++-------
> >>   1 file changed, 4 insertions(+), 7 deletions(-)
> >>
> >> diff --git a/hw/display/macfb.c b/hw/display/macfb.c
> >> index 4b352eb89c3f..277d3e663331 100644
> >> --- a/hw/display/macfb.c
> >> +++ b/hw/display/macfb.c
> >> @@ -440,21 +440,18 @@ static MacFbMode *macfb_find_mode(MacfbDisplayType display_type,
> >>
> >>   static gchar *macfb_mode_list(void)
> >>   {
> >> -    gchar *list = NULL;
> >> -    gchar *mode;
> >> +    GString *list = g_string_new("");
> >>       MacFbMode *macfb_mode;
> >>       int i;
> >>
> >>       for (i = 0; i < ARRAY_SIZE(macfb_mode_table); i++) {
> >>           macfb_mode = &macfb_mode_table[i];
> >>
> >> -        mode = g_strdup_printf("    %dx%dx%d\n", macfb_mode->width,
> >> +        g_string_append_printf(list, "    %dx%dx%d\n", macfb_mode->width,
> >>                                  macfb_mode->height, macfb_mode->depth);
> >> -        list = g_strconcat(mode, list, NULL);
> >> -        g_free(mode);
> >>       }
> >>
> >> -    return list;
> >> +    return g_string_free(list, FALSE);
> >
> > This reverses the order compared to the old code (which prepends
> > 'mode' to the 'list' string it is building up). Does that matter ?
> >
>
> Not at all. Perhaps it's even better like that as we have lower resolutions first.

In that case,
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM

Re: [PATCH] macfb: fix a memory leak (CID 1465231)

[Mark Cave-Ayland]

On 05/11/2021 16:52, Laurent Vivier wrote:

> Rewrite the function using g_string_append_printf() rather than
> g_strdup_printf()/g_strconcat().
> 
> Fixes: df8abbbadf74 ("macfb: add common monitor modes supported by the MacOS toolbox ROM")
> Cc: mark.cave-ayland@ilande.co.uk
> Reported-by: Peter Maydell <peter.maydell@linaro.org>
> Suggested-by: Peter Maydell <peter.maydell@linaro.org>
> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
> ---
>   hw/display/macfb.c | 11 ++++-------
>   1 file changed, 4 insertions(+), 7 deletions(-)
> 
> diff --git a/hw/display/macfb.c b/hw/display/macfb.c
> index 4b352eb89c3f..277d3e663331 100644
> --- a/hw/display/macfb.c
> +++ b/hw/display/macfb.c
> @@ -440,21 +440,18 @@ static MacFbMode *macfb_find_mode(MacfbDisplayType display_type,
>   
>   static gchar *macfb_mode_list(void)
>   {
> -    gchar *list = NULL;
> -    gchar *mode;
> +    GString *list = g_string_new("");
>       MacFbMode *macfb_mode;
>       int i;
>   
>       for (i = 0; i < ARRAY_SIZE(macfb_mode_table); i++) {
>           macfb_mode = &macfb_mode_table[i];
>   
> -        mode = g_strdup_printf("    %dx%dx%d\n", macfb_mode->width,
> +        g_string_append_printf(list, "    %dx%dx%d\n", macfb_mode->width,
>                                  macfb_mode->height, macfb_mode->depth);
> -        list = g_strconcat(mode, list, NULL);
> -        g_free(mode);
>       }
>   
> -    return list;
> +    return g_string_free(list, FALSE);
>   }
>   
>   
> @@ -643,7 +640,7 @@ static bool macfb_common_realize(DeviceState *dev, MacfbState *s, Error **errp)
>           gchar *list;
>           error_setg(errp, "unknown display mode: width %d, height %d, depth %d",
>                      s->width, s->height, s->depth);
> -        list =  macfb_mode_list();
> +        list = macfb_mode_list();
>           error_append_hint(errp, "Available modes:\n%s", list);
>           g_free(list);

Thanks Laurent, looks good to me.

Reviewed-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>


ATB,

Mark.